A 32-year-old multiparous woman (G3P2) at 34 weeks of gestation presents to the emergency department with painless vaginal bleeding of 200 mL. She denies abdominal pain, contractions, or leakage of fluid. Vital signs: BP 128/82 mmHg, HR 92 bpm, RR 18/min. On speculum examination, blood is seen pooling in the vagina; no cervical lesions or polyps are noted. Transabdominal ultrasound shows the placenta covering the internal cervical os completely. The fetal heart rate is 148 bpm with normal variability. What is the most appropriate immediate management?